Phyllotaxy
Study of the pattern of arrangement of leaves on the stem or branch (alternate, opposite, whorled).
What is Phyllotaxy?
The arrangement of leaves on the stem of a plant.
Key points
- Define phyllotaxy.
- Identify and differentiate between alternate, opposite, and whorled phyllotaxy.
- Provide examples of plants for each type.
- Explain the adaptive significance of phyllotaxy.
Common exam trap
Confusing opposite and whorled arrangements.
Definitions
- Term
Phyllotaxy
- Meaning
The arrangement of leaves on the stem of a plant.
- Term
Node
- Meaning
The part of a plant stem where a leaf or branch grows.
- Term
Alternate Phyllotaxy
- Meaning
A pattern where a single leaf arises at each node, with successive leaves on opposite sides.
- Term
Opposite Phyllotaxy
- Meaning
A pattern where two leaves arise at each node, growing from opposite sides of the stem.
- Term
Whorled Phyllotaxy
- Meaning
A pattern where three or more leaves arise at each node, forming a whorl.
- Term
Decussate Phyllotaxy
- Meaning
A type of opposite phyllotaxy where successive pairs of leaves are arranged at right angles to each other.
Learning objectives
Define phyllotaxy.
Identify and differentiate between alternate, opposite, and whorled phyllotaxy.
Provide examples of plants for each type.
Explain the adaptive significance of phyllotaxy.
Prerequisites
Basic plant morphology (stem, node, leaf).
Understanding of photosynthesis.
Common mistakes
Confusing opposite and whorled arrangements.
Not recognizing decussate as a subtype of opposite.
Assuming leaf arrangement is random.
Keywords
Phyllotaxy
Leaf arrangement
Alternate
Opposite
Whorled
Node
Stem
Plant morphology
Photosynthesis
Decussate
Practice preview
Identify the phyllotaxy where three or more leaves arise at each node, forming a ring around the stem.…
easy
Which of the following is an example of a plant exhibiting alternate phyllotaxy?…
medium
Which of the following statements about phyllotaxy is INCORRECT?…
medium